Problem: Khan.scratchpad.disable(); Christopher sells magazine subscriptions and earns $$6$ for every new subscriber he signs up. Christopher also earns a $$32$ weekly bonus regardless of how many magazine subscriptions he sells. If Christopher wants to earn at least $$85$ this week, what is the minimum number of subscriptions he needs to sell?
Solution: To solve this, let's set up an expression to show how much money Christopher will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Christopher wants to make at least $$85$ this week, we can turn this into an inequality. Amount earned this week $\geq $85$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $85$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $6 + $32 \geq $85$ $ x \cdot $6 \geq $85 - $32 $ $ x \cdot $6 \geq $53 $ $x \geq \dfrac{53}{6} \approx 8.83$ Since Christopher cannot sell parts of subscriptions, we round $8.83$ up to $9$ Christopher must sell at least 9 subscriptions this week.